In recent years, companies have invested significantly in the research and development of technology for remotely controlling construction machines such as hydraulic excavators, bulldozers or dump trucks, and track-type tractors. Particularly in working sites that are dangerous for workers to enter, such as a site for restoration against natural calamities or the construction of a dam, a quarry, or an iron mill, machines are controlled through a remote operating station. The machine can be employed on an actual worksite, while the remote operating station can be positioned indoors. Machine operators interface with machines through a control panel in the remote operating station. The operator continuously monitors the machine on a display device of the remote operating station. The display device is used to indicate the state of the machine. In other words, the display device indicates the machine's movement, such as speed or direction. However, in various work areas, machines usually work on grades and/or slopes. In such a scenario, information regarding the orientation or attitude of the machine is important for the operator to control the machine.
It can be imperative for the operator to know the attitude parameters such as pitch and roll of the machine. Pitch is the angle of the wheel base or track frame of machine while moving up/down on a slope. In other words, if a machine is moving up/down an incline, it has a certain pitch with respect to horizontal. On the other hand, if a machine is banked or tilted towards left of right, it is said to have a certain roll with respect to horizontal. In other words, pivotal movement about the transverse axis is called pitch, and rotation about the longitudinal axis of the machine is termed as roll. The operator can use information on both pitch and roll to control the machine. If the pitch is beyond a threshold level, the machine engine can stall or the machine can topple. On the other hand, if the roll exceeds a threshold value, the machine can capsize and tumble to the side.
Presently, there are several ways to indicate machine attitude. The indicating devices have been commonly mounted on the machine. For example, U.S. Pat. No. 3,846,781 discloses an indicating device having a pendulum and a pointer arrangement. The pendulum and the point arrangement are attached to the machine. The pendulum moves in the longitudinal direction and the pointer is configured to move in a transverse direction to indicate the pitch and roll of the machine, respectively. The disclosed arrangement is a mechanical assembly that indicates the sideward slope and the up and down slope of the machine. Another existing indicating device to indicate the pitch and roll can be found in the domain of aircraft. For example, 2006 US publication 0212182 describes a pitch and roll indicator display, where the movement of the horizon relative to a fixed aircraft symbol indicates the pitch and roll of the aircraft.
There is a need for indicating attitude of the machine at the remote operating station that is used to operate a machine from a remote location.